Ultraviolet radiation has been used to inactivate pathogens in water and air since the 1920's; adsorbents have been used to clean water for far longer. One commercially available product from eSpring™ [www.eSpring.com; Dec. 5, 2005] offers an ultraviolet lamp plus carbon block home device for treating water; a caution on the product advises “The eSpring Water Purifier is designed for use with any municipally treated drinking water source or potable well/bore water. It is not intended for use on lake, river, or any other non-approved water sources.”. Two points, the “carbon block” described appears to be functioning as a very fine filter and not making use of any porous properties of activated carbon; secondly, why one would treat potable water with an ultra-violet lamp is not apparent. The technology to clean water to virtually any level of purity desired has been available for some time; the semiconductor industry has fostered the use of ultra-clean chemicals, including water, since its inception. However, technology is not the issue; cost is the issue. The scarcity of potable drinking water in the third world at an affordable price is a problem the instant invention seeks to alleviate.
U.S. Pat. No. 5,942,110 reviews the prior art including different chamber and lamp configurations. [110] teaches a wall mounted treatment apparatus with inner and outer sleeves, internal mirrored surface, o-ring gaskets and many different components. [110] is a good example of a well built uv treatment apparatus that is far too expensive for a mass market. U.S. Pat. No. 6,583,422 teaches a chamber tube, replaceable clamps and a length adjustable chamber tube; this design is less expensive than [110] however it is not simple enough and it utilizes only one technology; the invention can not purify water with organic or inorganic contaminants. U.S. 2003/0129105 teaches a disinfection reactor with a plurality of quartz sleeves and uv lamps positioned perpendicular to the water flow; again this design is too expensive for mass appeal. U.S. 2005/0016907 teaches an electro-optical water purifier with a spiral pipeline and a plurality of uv emission tubes; this apparatus is overly complex and expensive.
Typical household water filters containing carbon have limited effectiveness with regard to pathogens and metals. Carbon by itself is quite good for removing chlorine and a few other taste degrading compounds but has marginal purification capability. In addition, if used incorrectly carbon becomes a breeding ground for pathogens.
All of the prior art suffer from high cost and failure to integrate synergistic technologies to achieve acceptable water purification under a broad range of conditions. A simple solution is needed which achieves multi-contaminant water purification and low cost.